Electric horn

ABSTRACT

An electric horn is provided which comprises a vortical acoustic transformer having a sound inlet port, an electromagnetic vibrating mechanism disposed at a central portion of the transformer and having an armature, a diaphragm mounted, along with the armature, on the transformer so as to enclose the sound inlet port, and a vibrator fixed to the diaphragm at a position opposite to the transformer.

United States Patent 11 Ueda 1 May 27, 1975 1 ELECTRIC HORN [75]inventor:

[73] Assignee: Nippondenso Co., Ltd., Kariya-shi,

Japan [22] Filed: Apr. 13,1973

[21] Appl. No: 351,037

Mitsuru Ueda, Kariya, Japan FORElGN PATENTS OR APPLICATIQNS 969,2744/1964 France 340/388 Primary Examiner.lohn W. Caldwell AssistantExaminerWilliam M. Wannisky Attorney, Agenl, 0r Firm-Cushman, Darby &Cushman [57] ABSTRACT An electric horn is provided which comprises avortical acoustic transformer having a sound inlet port, anelectromagnetic vibrating mechanism disposed at a central portion of thetransformer and having an armature, a diaphragm mounted, along with thearmature, on the transformer so as to enclose the sound inlet port, anda vibrator fixed to the diaphragm at a position opposite to thetransformer.

3 Claims, 6 Drawing Figures Pat'eni a May 27, 1975 2 Sheets-Sheet 1 F IG. I PRIOR ART F l G. 2 PRIOR ART Patented May 27, 1975 3,886,546

2 Sheets-Sheet 2 FG. 4 [dB] PRIOR ART Ff loo J L NILL To a l I006 800'?)[Hz] FlG. 5 PRIOR ART PM] M 1 mo "f F IG. 6

[d8] P 1 h 506 i065 i600 8006 [Hz] ELECTRIC HORN BACKGROUND OF THEINVENTION 1. Field of the Invention The present invention relates toimprovements in the tone quality and acoustic efficiency of an electrichorn used primarily on a motor vehicle.

2. Description of the Prior Art Electric horns heretofore usedextensively include the vortex type horn shown in FIG. I of theaccompanying drawings and the flat type horn shown in FIG. 2. However,these two types are contrary in their characteristics. In other words,with respect to the tone, the former, i.e., the vortex type horn hascharacteristics such that, as will be seen from FIG. 4 showing aspectrum diagram of the sound pressure p (dB) plotted against thefrequencyf( Hz), the level of the fundamental frequency corresponding tothe number of vibrations of a diaphragm 7 is prominent, the maximumharmonic level appears between I000 and 2000 Hz and is graduallydecreases as the frequency increases. thus providing a tone which issoft and mellow on the whole. On the other hand, the latter, ie. theflat type horn has characteristics such that, as will be seen from thespectrum diagram shown in FIG. 5, the level of the fundamental frequencyis relatively low, the sound pressure main component having a very highlevel appears in the vicinity of 2000 to 3000 Hz and it rapidlydecreases as the frequency increases with a higher harmonic levelreappearing in the vicinity of 8000 Hz, thus providing a tone which ismaterially monotonous and highly jarring on the whole. Further, theformer vortex type horn has a drawback in that since the sound producedby the vibrations of the diaphram 7 is indirectly emitted through avortical acoustic transformer l (hereinafter referred to as a trumpet),the propagation directivity of the sound is poor. In contrast, while thelatter flat type horn has a remarkable directivity and high acousticefficiency owing to the fact that the sound produced by the vibrationsof a resonant vibrator 9 (hereinafter simply referred to as a vibrator)is directly emitted to the atmosphere in the form of a plane wave, ithas a drawback in that since the sound produced by this horn is highlyjarring as previously mentioned, it causes a feeling of unpleasantnesson the part of the people.

SUMMARY OF THE INVENTION It is the object of the present invention toprovide an electric horn which overcomes the foregoing difficulty andwhich comprises an electromagnetic vibrating mechanism disposed at thecentral portion of a vortical trumpet. a diaphragm mounted to thearmature of the vibrating mechanism to enclose the sound inlet port ofthe trumpet, and a vibrator mounted to the armature on the outside ofthe diaphragm in direct contact with the atmosphere, whereby the desiredcharacteristic of the vortex type horn and the flat type horn arecombined to produce an entirely new tone and maintain the emissionefficiency of the sound to the atmosphere at a high level.

According to the present invention. an electromagnetic vibratingmechanism is disposed at the central portion of a vortical acoustictransformer with a dia phragm mounted to the armature of the vibratingmechanism to enclose the sound inlet port of the acoustic transformer.and a vibrator is mounted to the armature on the outside of thediaphragm in direct contact with the atmosphere, whereby the independentvibrating motions of the diaphragm and the vibrator are caused to act inthe same dimension. that is, the same effect as would be obtained by thesimultaneous operation of the vortex type horn and the flat type horn isensured by the single horn. Thus, there is a great advantage in that thepresent invention provides a highly efficient novel horn which is ofsimple structure and inexpensive to manufacture and in which inferiorperformance of the vortex type horn in respect of the acousticefficiency and emission directivity is compensated by the acousticcharacteristic of the vibrator and moreover the highly jarring tone ofthe flat type horn is mitigated by the acoustic characteristic of theacoustic transformer to thereby produce an entirely new tone.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a longitudinal side sectionalview of a con ventional vortical electric horn;

FIG. 2 is a longitudinal side sectional view of a conventional flatelectric horn;

FIG. 3 is a longitudinal side sectional view showing an embodiment of anelectric horn according to the present invention;

FIG. 4 is a frequency spectrum diagram showing the tone components ofthe vertical electric horn shown in FIG. 1;

FIG. 5 is a frequency spectrum diagram showing the tone components ofthe flat electric horn shown in FIG. 2; and

FIG. 6 is a frequency spectrum diagram showing the tone components ofthe electric horn according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawingswherein the same ref erence numerals refer to the same or equivalentcomponent parts, the preferred embodiment of the invention will beexplained. In FIG. 3, numeral 1 designates a vortical trumpet withnumeral la designating its sound inlet port, lb its sound path. 16 itsmouth and la its shell flat portion. Numeral 2 designates anelectromagnet disposed at the central portion of the trumpet 1, 2a itsiron core. 2b an energizing winding wound on the core 2a. Numeral 3designates an interrupter for interrupting the supply of current to theenergizing winding 2b, 4 an armature disposed at a position opposite tothe core 20, 5 an interrupter actuator for controlling opening andclosing of the interrupter 3 in accordance with the reciprocatingmovement of the armature 4. Numerals 6 and 6' designate magnetic pathmembers for providing a magnetic path between the electromagnet 2 andthe armature 4. The electromagnet 2, the interrupter 3, the armature 4and so on constitute an electromagnetic vibrating mechanism. Numeral 7designates a diaphragm securely mounted at the central portion thereofon the armature 4 and clamped at the peripheral edges thereof on theperipheral portions of the shell flat portion Id to enclose the soundinlet port Ia of the trumpet l and define a narrow air chamber 8 betweenthe diaphragm 7 and the shell flat portion Id. Numeral 9 designates avibrator securely mounted to the armature 4 on the outside of thediaphragm 7 in direct contact with the atmosphere.

With the construction described above, the electric horn according tothe present invention operates as follows: When a current is supplied tothe energizing winding 2b, the diaphragm 7 vibrates rapidly by virtue ofthe provision of the interrupter 3 and thus the air within the airchamber 8 is rapidly compressed and expanded in response to thevibrations of the diaphragm 7, thereby producing an impulsive sound.Consequently, this sound is emitted into the sound inlet port la of thetrumpet I, so that sound is propagated through the sound path lb to themouth 10 from which the sound is emitted to the atmosphere.

On the other hand, since the vibrator 9 is securely mounted to thediaphragm 7 on the side thereof where it comes into direct contact withthe atmosphere, a socalled resonant state is caused by the naturalvibrations of the vibrator 9 which are so related as to produceharmonies and consequently the amplified sound output is emitteddirectly to the atmosphere.

As a result, the tone emitted from the mouth 1c of the trumpet l andhaving a low acoustic efficiency and inferior emission directivity iscompensated by the acoustic characteristic of the vibrator 9, while thehighly jarring sound produced by the vibrator 9 is softened by the soundproduced by the trumpet 1.

Further, since the vortical trumpet 1 serves concurrently as an acoustictransformer and as a resonant tube for the air column vibrations, itsresonant frequency is approximately in the order of 1000 H2 and it doesnot change much depending on the length and dimension of the trumpet 1.However, there are a number of factors, such as the shape, dimension,weight, material and so on which affect the resonant frequency, theresonant frequency of the vibrator 9 may be selected as desired to someextent. Furthermore, since the trumpet 1 and the vibrator 9 are quiteindependent of each other, when considered primarily on the basis of theemitting sound pressure, it is sufficient if the natural frequency ofthe vibrator 9 is set to a so-called resonant frequency whichcorresponds to the resonance frequency of the trumpet 1. In addition,there is a great convenience in that by intentionally deviating thefrequency of the vi brator, it is possible to produce a unique tone. Thespectrum diagram of FIG. 6 showing the relationship between thefrequency f(Hz) and the sound pressure p (dB) represents the case of thehorn according to the embodiment described hereinbefore and it isapproximately the same with the spectrum diagrams of FIGS. 4 and 5combined together.

I claim:

1. An electric horn comprising a vortical acoustic transformer having asound inlet port, an electromagnet fixedly secured on said transformerat the center thereof, means for energizing said electromagnet, interrupting means for interrupting the energizing current to saidelectromagnet, a movable armature disposed proximate said electromagnet,said armature being attracted to said electromagnet when energized bysaid energizing current, a diaphragm having a portion thereof fixedlysecured to said transformer and having another portion thereof fixedlysecured to said armature, said diaphragm being moved in accordance withthe movement of said armature, said diaphragm enclosing the sound inletport of said transformer, and a vibrator fixedly secured to saiddiaphragm and said armature on the side of said diaphragm opposite saidtransformer.

2. The electric horn of claim 1 wherein said interrupter means includesat least one movable contact, said contact being separated from anotherstationary contact by the movement of said armature toward saidelectromagnet, said contacts being closed when said armature moves awayfrom said electromagnet.

3. An electric horn comprising a vortical acoustic transformer having asound inlet port proximate a central portion thereof,

an electromagnet fixedly secured to the central portion of saidtransformer within said sound inlet port,

a diaphragm fixedly secured to said transformer and extending over saidsound inlet port,

an armature fixedly secured to a central portion of said diaphragm andbeing positioned in proximity to and in reciprocating relationship withsaid electromagnet, said diaphragm and said armature enclosing saidinlet port,

means for energizing said electromagnet,

an interrupter means for intermittently interrupting the energization ofsaid electromagnet, and

a vibrator fixedly secured to said diaphragm on the side of saiddiaphragm opposite to said transformer.

1. An electric horn comprising a vortical acoustic transformer having asound inlet port, an electromagnet fixedly secured on said transformerat the center thereof, means for energizing said electromagnet,interrupting means for interrupting the energizing current to saidelectromagnet, a movable armature disposed proximate said electromagnet,said armature being attracted to said electromagnet when energized bysaid energizing current, a diaphragm having a portion thereof fixedlysecured to said transformer and having another portion thereof fixedlysecured to said armature, said diaphragm being moved in accordance withthe movement of said armature, said diaphragm enclosing the sound inletport of said transformer, and a vibrator fixedly secured to saiddiaphragm and said armature on the side of said diaphragm opposite saidtransformer.
 2. The electric horn of claim 1 wherein said interruptermeans includes at least one movable contact, said contact beingseparated from another stationary contact by the movement of saidarmature toward said electromagnet, said contacts being closed when saidarmature moves away from said electromagnet.
 3. An electric horncomprising a vortical acoustic transformer having a sound inlet portproximate a central portion thereof, an electromagnet fixedly secured tothe central portion of said transformer within said sound inlet port, adiaphragm fixedly secured to said transformer and extending over saidsound inlet port, an armature fixedly secured to a central portion ofsaid diaphragm and being positioned in proximity to and in reciprocatingrelationship with said electromagnet, said diaphragm and said armatureenclosing said inlet port, means for energizing said electromagnet, aninterrupter means for intermittently interrupting the energization ofsaid electromagnet, and a Vibrator fixedly secured to said diaphragm onthe side of said diaphragm opposite to said transformer.